Motor vehicles typically include an internal combustion engine and an associated lubrication system for providing lubricating oil to various areas of the engine. The various areas can include bearings that support rotating shafts, such as a crankshaft and a camshaft, for example. The engine typically requires a certain flow rate of oil to be delivered to these various areas within a certain range of pressure, where the flow rate and pressure vary depending on the engine speed (i.e., crankshaft rotation speed). A conventional fixed displacement oil pump can be used to deliver lubricating oil to the various lubrication areas. However, such a conventional fixed displacement oil pump can produce less oil pressure than desired when operating at a high engine temperature and low engine speed condition. In addition, the fixed displacement oil pump can also produce excessively high oil pressure when operating at a high engine speed and low engine temperature condition. Increasing the displacement of such a fixed displacement pump to improve the oil pressure at the high temperature and low engine speed operating condition can result in more power consumption and thus a degradation in fuel economy while also increasing the oil pressure at the high engine speed and low temperature condition.
Thus, while fixed displacement oil pumps work for their intended purpose, there remains a need for continuous improvement in the relevant art.